[Eeglablist] Extracting ERP values after MPT clustering

[Makoto Miyakoshi]

Dear Mohammed,

Sorry to hear the inconvenience. This is a good detailed question. I
believe this should be posted for eeglab Bugzilla to be officially
registered. Would you mind filing the report here? I appreciate your
cooperation and patience.
https://sccn.ucsd.edu/bugzilla/enter_bug.cgi

That being said, I recently noticed that Measure Projection could have a
potential problem of double dipping (because you cluster data using ERP,
for example, and run statistics on that later). It's probably safer to use
anatomical regions, not domains (but that may not be supported by GUI).

Makoto

On Mon, Apr 18, 2016 at 10:49 AM, Mohammed Jarjees <
m.jarjees.1 at research.gla.ac.uk> wrote:

> Dear All,
>
>
>
> I am using  Measure projection toolbox (MPT) to cluster my EEG (ERP) data.
> In this study I have 3 groups of subjects ( First group has 10 subjects,
> second group has 9 subjects and third group has 10 subjects) and I have 3
> conditions per group. I got 3 domains after MPT clustering. I extracted the
> ERP values from “sessionConditionCell” for each domains. The size of
> “sessionConditionCell” is 29*3 (subjects*conditions). I have used the
> following codes to extract the ERP values and to separate these values for
> each group and each condition.
>
>
>
> domainNumber = 1; % this should be 1,2 or 3%
>
> dipoleAndMeasure = STUDY.measureProjection.erp.object;
>
> domain                         =
> STUDY.measureProjection.erp.projection.domain(domainNumber);
>
> projection                   = STUDY.measureProjection.erp.projection;
>
> headGrid                     = STUDY.measureProjection.erp.headGrid;
>
> [linearProjectedMeasure sessionConditionCell groupId uniqeDatasetId
> dipoleDensity]  =
> dipoleAndMeasure.getMeanProjectedMeasureForEachSession(headGrid,
> domain.membershipCube, projection.projectionParameter);
>
>
>
> for i =1 : 29 ;
>
> Condition_1 ( i , : )= sessionConditionCell { i, 1};
>
> Condition_2 ( i , : )= sessionConditionCell { i, 2};
>
> Condition_3 ( i , : )= sessionConditionCell { i, 3};
>
> end
>
>
>
> Group_1_Condition_1= Condition_1 ( 1:10, : );     Group_2_Condition_1=
> Condition_1 ( 11:19, : );     Group_3_Condition_1= Condition_1 ( 20:29, : );
>
> Group_1_Condition_2= Condition_2 ( 1:10, : );     Group_2_Condition_2=
> Condition_2 ( 11:19, : );     Group_3_Condition_2= Condition_2 ( 20:29, : );
>
> Group_1_Condition_3= Condition_3 ( 1:10, : );     Group_2_Condition_3=
> Condition_3 ( 11:19, : );     Group_3_Condition_3= Condition_3 ( 20:29, : );
>
>
>
> When I plotted the average ERP for each condition, each group and each
> domain, I got different in* some* results from the results that I got
> from MPT GUI. For example the results for group 1 at Domain 1 for 3
> conditions are same as the results from MPT GUI as well as the result for
> domain 2 and all three group and three condition are same as the MPT GUI.
> However, there are big different for group 2 & 3 at domain 1 as well as
> group 2 & 3 at domain 3 for all three conditions.
>
>
>
> Any Suggestion to solve this problem
>
>
>
> Best Regards
>
> Mohammed
>
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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